Companies that rely on broadcast video and/or audio programs for revenue, such as advertisers, television networks and content providers, wish to know the size and demographic composition of the audience(s) that consume their program(s). Audience measurement companies address this need by measuring the demographic composition of a set of statistically selected households and the program consumption habits of the member(s) of those households. For example, audience measurement companies may collect viewing data on a selected household by monitoring the content displayed on that household's television(s) and by identifying which household member(s) are watching that content.
Traditionally, broadcast programs have been consumed at the time of broadcast. Therefore, it was safe to assume that audience members using an information presenting device such as a television or radio consumed the entire broadcast stream during the period in which the information presenting device was in use. Recently, however, recording devices such as audio cassette players, video cassette recorders (VCR's), set top boxes, digital video recorders, and personal video recorders, such as SonicBlue's ReplayTV®, TiVo® and other devices that permit content to be recorded and replayed in accordance with the desires of the audience members have become commonplace. These devices have increased the audience members' ability to time shift the consumption of broadcast programs (i.e., to record a program at the time of broadcast and consume that same program at a later time that suits the consumer). This ability to time shift has also provided the consumer with enhanced power to consume only selected portions of broadcast programs by, for example, skipping or fast-forwarding through portions of recorded content. Some consumers have used this enhanced ability to avoid viewing advertising commercials or other portions of the broadcast program.